diff options
Diffstat (limited to 'arch/arm/lib/bitops.h')
| -rw-r--r-- | arch/arm/lib/bitops.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h new file mode 100644 index 00000000..10d868a5 --- /dev/null +++ b/arch/arm/lib/bitops.h @@ -0,0 +1,77 @@ +#if __LINUX_ARM_ARCH__ >= 6 + .macro bitop, instr + ands ip, r1, #3 + strneb r1, [ip] @ assert word-aligned + mov r2, #1 + and r3, r0, #31 @ Get bit offset + mov r0, r0, lsr #5 + add r1, r1, r0, lsl #2 @ Get word offset + mov r3, r2, lsl r3 +1: ldrex r2, [r1] + \instr r2, r2, r3 + strex r0, r2, [r1] + cmp r0, #0 + bne 1b + bx lr + .endm + + .macro testop, instr, store + ands ip, r1, #3 + strneb r1, [ip] @ assert word-aligned + mov r2, #1 + and r3, r0, #31 @ Get bit offset + mov r0, r0, lsr #5 + add r1, r1, r0, lsl #2 @ Get word offset + mov r3, r2, lsl r3 @ create mask + smp_dmb +1: ldrex r2, [r1] + ands r0, r2, r3 @ save old value of bit + \instr r2, r2, r3 @ toggle bit + strex ip, r2, [r1] + cmp ip, #0 + bne 1b + smp_dmb + cmp r0, #0 + movne r0, #1 +2: bx lr + .endm +#else + .macro bitop, instr + ands ip, r1, #3 + strneb r1, [ip] @ assert word-aligned + and r2, r0, #31 + mov r0, r0, lsr #5 + mov r3, #1 + mov r3, r3, lsl r2 + save_and_disable_irqs ip + ldr r2, [r1, r0, lsl #2] + \instr r2, r2, r3 + str r2, [r1, r0, lsl #2] + restore_irqs ip + mov pc, lr + .endm + +/** + * testop - implement a test_and_xxx_bit operation. + * @instr: operational instruction + * @store: store instruction + * + * Note: we can trivially conditionalise the store instruction + * to avoid dirtying the data cache. + */ + .macro testop, instr, store + ands ip, r1, #3 + strneb r1, [ip] @ assert word-aligned + and r3, r0, #31 + mov r0, r0, lsr #5 + save_and_disable_irqs ip + ldr r2, [r1, r0, lsl #2]! + mov r0, #1 + tst r2, r0, lsl r3 + \instr r2, r2, r0, lsl r3 + \store r2, [r1] + moveq r0, #0 + restore_irqs ip + mov pc, lr + .endm +#endif |